1. Field of the Invention
The present invention relates to a Gauss type photographic lens system having a large aperture ratio on the order of F 1.8.
2. Description of the Prior Art
In conventional Gauss type lens system, it is considered advantageous for correcting flare due to coma to separate a cemented surface of a cemented lens component which is arranged on the object side of a stop. Though separation of such a cemented lens component is advantageous for correcting flare due to coma, it has a drawback that it aggravates asymmetry of coma produced by rays around the principal ray.
An effective means for eliminating this drawback is to widen the airspace between negative meniscus lens components having strong powers arranged on both sides of an aperture stop. However, such a means will unavoidably increase Petzval's sum, thereby aggravating curvature of field and producing spherical aberration.